1. Field of the Invention
The present invention relates to a chlorine-containing polymer vulcanizing composition such as represented by chlorinated polyethylene or epichlorohydrin polymer, and to a vulcanized product thereof.
2. Description of the Prior Art
Generally, a chlorine-containing polymer is widely used as a material for a rubber product or a resin product, or as a material for an adhesive or a paint because of its excellent heat resistance, oil resistance, weather resistance, ozone resistance, and abrasion resistance. In particular, chlorinated polyethylene is attracting people""s attention as a rubber material utilizing its excellent heat resistance, oil resistance, weather resistance, and ozone resistance.
Various proposals have already been made for vulcanization of chlorinated polyethylene. For example, organic peroxides and various sulphur-containing compounds such as mercaptotriazines are proposed as a vulcanizing agent for chlorinated polyethylene. It is also known to use various organic vulcanization accelerators such as an amine compound in combination with the vulcanizing agent for accelerating vulcanization of chlorinated polyethylene. It is a common knowledge of those skilled in the art that an acid receiving agent must be blended with a vulcanizing composition for absorbing an acid component generated in a small amount in vulcanizing chlorinated polyethylene. For example, Japanese Examined Patent Publication No. 55-39250/1980 proposes a metal compound selected from the group consisting of oxide, hydroxide, carboxylate, silicate, carbonate, phosphite, borate, basic sulfite and tribasic sulfate of a group IVA metal in the periodic table, as the acid receiving agent.
A vulcanizing composition disclosed in Japanese Laid-open Patent Publication 63-28047/1988 provides stability of a vulcanized product and a suitable vulcanization speed, and the patent publication gives oxide, hydroxide, carboxylate, silicate, carbonate, phosphite and borate of a group II metal in the periodic table, and oxide, basic phosphite, basic carbonate, basic carboxylate, basic sulfite, and tribasic sulfate of a group IVA metal in the periodic table as example of the metal compounds. Specific examples thereof include magnesia, magnesium hydroxide, barium hydroxide, magnesium carbonate, barium carbonate, slaked lime, quick lime, calcium carbonate, calcium silicate, calcium stearate, zinc stearate, calcium phthalate, magnesium phosphite, calcium phosphite, zinc white, tin oxide, litharge, red lead, white lead, dibasic lead phthalate, dibasic lead carbonate, tin stearate, basic lead phosphite, basic tin phosphite, basic lead sulfite and tribasic lead sulfate.
Japanese Laid-open Patent Publication 53-3439/1978, 54-58750/1979, 09-176433/1997, and others disclose a vulcanizing composition containing a thiadiazole compound as a vulcanizing agent for a chlorine-containing polymer, in which a basic metal oxide, a basic metal salt, a basic metal hydroxide, or the like is used as a compounding agent.
However, none of these vulcanizing compositions is a composition obtained by blending a zeolite compound as an acid receiving agent with a chlorine-containing polymer. Although these vulcanizing compositions provide vulcanized products having good vulcanization properties and are put into industrial use, they have a poor preservation stability and involves various restrictions in industrial rubber processing. For example, if the preservation stability of the vulcanizing composition is poor, vulcanization proceeds during preservation to make vulcanization molding impossible, whereby the vulcanizing composition must be discarded, desired vulcanization properties can not be obtained, or a dimension precision is greatly reduced, even though the vulcanization molding can be carried out.
Japanese Examined Patent Publication 58-18939/1983 discloses blending a specific aluminosilicate as a heat stabilizer with a chlorine-containing polymer. However, this does not contain a vulcanizing agent, i.e. is not one obtained by blending an aluminosilicate with a vulcanizing composition, much less gives a teaching of preservation stability of the vulcanizing composition.
Japanese Laid-open Patent Publications 07-157566/1995 and 07-286098/1995 disclose a polymer vulcanizing composition containing an epichlorohydrin polymer, a mercapto vulcanizing agent, and a hydrotalcite. However, this vulcanizing composition is not one obtained by blending a zeolite compound as an acid receiving agent.
Japanese Laid-open Patent Application 60-233138/1985 discloses a composition containing a chlorosulfonated polyolefin, an epoxy compound, and an A-type zeolite. However, this is a disclosure that the A-type zeolite preserves a white color of the chlorosulfonated polyolefin at the time of heating and increases the strength of the vulcanized product, and it also fails to give a teaching on the preservation stability of the vulcanizing composition.
In view of the above-mentioned circumstances, the object of the present invention is to provide a chlorine-containing polymer vulcanizing composition with improved preservation stability.
The inventors of the present invention have made various studies in order to solve the above problems, and found out that blending a zeolite compound as an acid receiving agent is effective in improving the preservation stability of a chlorine-containing polymer vulcanizing composition, thereby completing the present invention.
Accordingly, the present invention provides a chlorine-containing polymer vulcanizing composition obtained by blending with a chlorine-containing polymer, (a) a zeolite compound, (b) a vulcanizing agent, and (c) an optional organic vulcanization accelerator.
Further, the present invention provides a chlorine-containing polymer vulcanizing composition containing (d) an optional inorganic vulcanization accelerator in addition to the above-mentioned compounding agents (a), (b), and (c). By blending the (d) component, the vulcanization speed and the compression set can be improved.
The term xe2x80x9cchlorine-containing polymerxe2x80x9d as a major component of the composition is used to include a polymer with chlorine directly bonded to a main chain of the polymer or a polymer obtained using a chlorine-containing monomer as a main constituent element, such as chlorinated polyethylene, an epichlorohydrin polymer, polyvinyl chloride, chloroprene rubber, chlorinated natural rubber or chlorosulfonated polyethylene; a polymer containing a small amount of chlorine as a cross-linking point, such as chlorinated butyl rubber; an acrylic rubber obtained by copolymerizing an acrylic monomer with a chlorine-containing monomer; and others.
These polymers can be each a commercially available product, and can be used without special limitation.
Among the above chlorine-containing polymers, chlorinated polyethylene is obtained by chlorinating polyethylene powder or particles in an aqueous suspension or in an organic solvent. In the present invention, chlorinated polyethylene is preferably obtained by chlorination in an aqueous suspension. The polyethylene to be used as a raw material is a homopolymer of ethylene or a copolymer of ethylene with a copolymerable comonomer. Examples of the comonomers include a-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-pentene-1; acetates such as vinyl acetate and ethyl acetate; (meth)acrylic acid; and (meth)acrylic acid esters such as methyl (meth)acrylate and ethyl (meth)acrylate. The polyethylene has a weight-average molecular weight of preferably 40,000 to 700,000, more preferably 50,000 to 300,000.
The polyethylene to be used as a raw material can be a high density polyethylene and a blend of a high density polyethylene with a low density polyethylene.
The chlorine content of chlorinated polyethylene to be used in the present invention is preferably 20 to 50% by weight, more preferably 25 to 45% by weight, when the vulcanized product is to be used as a vulcanized rubber. If the chlorine content is too high or too low, the hardness of the composition to be obtained can be too high. An amorphous or substantially amorphous chlorinated polyethylene is preferable. If the vulcanized product is to be used as a vulcanized adhesive for rubber and metal, the chlorine content of the chlorinated polyethylene to be used in the present invention is preferably 50 to 75% by weight, more preferably 60 to 70% by weight. If the chlorine content is 50% by weight or lower, the adhesive power can be insufficient, whereas if the content is 75% by weight or higher, the chlorination takes a lot of time, so that it is not preferable.
Among the above chlorine-containing polymers, the epichlorohydrin polymer is a homopolymer of epichlorohydrin or a copolymer of epichlorohydrin with a copolymerable epoxide such as ethylene oxide, propylene oxide or allyl glycidyl ether. Examples of the epichlorohydrin polymers include epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-propylene oxide copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer and epichlorohydrin-ethylene oxide-propylene oxide-allyl glycidyl ether tetrapolymer. Among these, preferred polymers are epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer and epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer. More preferred polymers are epichlorohydrin-ethylene oxide copolymer and epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer. In these copolymers, it is preferable that an epichlorohydrin component is contained at least at 10 mol% in view of ensuring a practical vulcanization speed.
The molecular weight of the epichlorohydrin polymer is preferably ML1+4 (100xc2x0 C.)=about 30 to 150 typically in Mooney viscosity representation.
The chlorine content in the chlorosulfonated polyethylene to be used in the present invention is preferably 20 to 50% by weight, more preferably 25 to 45% by weight when it is to be used as a vulcanized rubber. If the chlorine content is too high or too low, the hardness of the obtained vulcanized rubber can be too high. The amount of the chlorosulfone group introduced as a vulcanizing point is preferably 1 to 2% by weight generally in terms of sulphur content. Usually, chlorosulfonated polyethylene having a molecular weight of ML1+4 (100xc2x0 C.)=about 20 to 150 in Mooney viscosity representation is used as it is. An amorphous or substantially amorphous chlorosulfonated polyethylene is preferable.
The chlorine-containing polymer can be a blend of a chlorine-containing polymer in a major proportion and another rubber and/or resin in a minor proportion. For example, the chlorinated polyethylene can be one obtained by blending a nitrile rubber, an acrylic rubber, or the like with chlorinated polyethylene. This blending is carried out for the purpose of improving oil resistance, heat resistance and others.
The zeolite compound (a) acts as an acid receiving agent, and greatly improves the preservation stability of the chlorine-containing polymer vulcanizing composition. This effect produced by using a zeolite compound as an acid receiving agent is unexpected and surprising.
The zeolite compound of the composition can be various kinds of zeolite, such as a natural zeolite, an A-type, X-type, or Y-type synthetic zeolite, a sodalite, a natural or synthetic mordenite, ZSM-5, or a metal substitution product thereof. These can be used either alone or in mixtures thereof. The metal in the metal substitution product is often sodium. It is preferable to use a zeolite compound which has a high acid receiving capability.
The method for producing synthetic zeolite is known. For example, in the hydrothermal synthesis method, oxide (base) of an alkali or alkali earth metal, alumina, silica, and water are used as starting materials, and these are allowed to react typically at a temperature of 100xc2x0 C. or more, followed by precipitation of a zeolite crystal. It is possible to use a natural silicate mineral, for example, kaoline or clay such as allophene, or a volcanic glass as a starting material. For example, Japanese Examined Patent Publication 26-1119/51 discloses a method in which an active silicic acid obtained by treating an acid clay (montmorillonite) with an acid is allowed to react with a dilute sodium aluminate to produce a synthetic zeolite.
As the zeolite compound, it is preferable to use an activated zeolite compound. The term xe2x80x9cactivated zeolite compoundxe2x80x9d stands for one which is substantially free from water. Such activation can be carried out by heating to dehydrate a zeolite compound at a temperature of 100xc2x0 C. or more in a dried air or nitrogen stream, or by introducing a zeolite compound at the time of kneading a chlorine-containing polymer with other components and exposing the resulting mixture to a kneading temperature of 140xc2x0 C. to 200xc2x0 C.
The vulcanizing agent is not specifically limited, and can be sulphur, a mercaptotriazine compound, a thiadiazole compound, 2,3-dimercaptoquinoxaline derivative, a thiourea compound, an amine, a thiuram compound, or the like.
The vulcanizing agent for chlorinated polyethylene is preferably a mercaptotriazine compound or a thiadiazole compound.
The mercaptotriazine compound can be a compound represented by the following general formula (I). 
In the formula (I), R is a group selected from the group consisting of a mercapto group, an alkoxy group, an alkylamino group, a dialkylamino group, a cycloalkylamino group, a dicycloalkylamino group and an arylamino group.
Specific examples of the mercaptotriazine compounds include 2,4,6-trimercapto-1,3,5-triazine, 1-methoxy-3,5-dimercaptotriazine, 1-hexylamino-3,5-dimercaptotriazine, 1-diethylamino-3,5-dimercaptotriazine, 1-cyclohexylamino-3,5-dimercaptotriazine, 1-dibutylamino-3,5-dimercaptotriazine, 2-anilino-4,6-dimercaptotriazine, 1-phenylamino-3,5-dimercaptotriazine.
The thiadiazole compound can be a compound represented by the following general formula (II), (III), (IV), or (V). 
In the formulae (II) and (III), R1 and R2 are identical or different, and represent a hydrogen atom, a group xe2x80x94(Cxe2x95x90O)R3, or a group xe2x80x94R4OR5, wherein R3 is an alkyl group having 1 to 17 carbon atoms, an aryl group having one or two ring(s), an acyl group having 7 to 14 carbon atoms, an aralkyl group having 7 to 8 carbon atoms, or a cyclohexyl group; and R4 and R5 are identical or different, and represent an alkyl group having 1 to 8 carbon atoms. 
In the formulae (IV) and (V), R6 and R7 are identical or different, and represent an alkyl group having 1 to 8 carbon atoms; R8 and R9 are identical or different, and represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms; n is 1 or 2; and X is an oxygen atom or a sulphur atom.
Specific examples of the thiadiazole compounds include 2,5-dimercapto-1,3,4-thiadiazole, a monobenzoate derivative of 2,5-dimercapto-1,3,4-thiadiazole, and a dibenzoate derivative of 2,5-dimercapto-1,3,4-thiadiazole, and preferred examples are 2,5-dimercapto-1,3,4-thiadiazole, 5-mercapto-1,3,4-thiadiazole-2-thiobenzoate, 1,3,4-thiadiazolyl-2,5-dithiobenzoate, 5-mercapto-1,3,4-thiadiazole-2-thiostearate, 5-mercapto-1,3,4-thiadiazole-2-thio-1-naphthoate, 5-mercapto-1,3,4-thiadiazole-2-thiophenylacetate, 5-mercapto-1,3,4-thiadiazole-2-thiocyclohexylcarboxylate, 5-mercapto-1,3,4-thiadiazole-2-thio-p-toluate, 5-mercapto-1,3,4-thiadiazole-2-thiocinnamate, 2,5-di(butoxymethyl)-1,3,4-thiadiazole, 2,2xe2x80x2-dimercapto-5,5xe2x80x2-dithiobis(1,3,4-thiadiazole), 2,2xe2x80x2-di(butoxymethyl)-5,5xe2x80x2-dithiobis(1,3,4-thiadiazole), and the like.
Preferred examples of the vulcanizing agents for epichlorohydrin polymers include 2,3-dimercaptoquinoxaline derivatives and thiourea compounds in addition to the above-mentioned mercaptotriazine compounds and thiadiazole compounds.
Examples of the 2,3-dimercaptoquinoxaline derivatives include quinoxaline-2,3-dithiocarbonate, 6-methylquinoxaline-2,3-dithiocarbonate, 6-isopropylquinoxaline-2,3-dithiocarbonate, 5,8-dimethylquinoxaline-2,3-dithiocarbonate, and the like.
The thiourea compounds can be thiourea compounds such as an ethylenethiourea compound, a dialkylthiourea compound, and a trialkylthiourea compound. Specific examples thereof include 2-mercaptoimidazoline, 1,3-diethylthiourea, 1,3-dibutylthiourea, trimethylthiourea and the like.
The vulcanizing agent for a chlorosulfonated polyethylene can be a thiuram compound. A specific example thereof is dipentamethylenethiuram tetrasulfide.
These vulcanizing agents can be used either singly or in combination of two or more.
The organic vulcanization accelerator (c) can be a member selected from the group consisting of a primary amine, a secondary amine, a tertiary amine, an organic acid salt or adduct of said amine, an aldehyde-ammonia compound, an aldehyde-amine compound, a guanidine compound, a thiazole compound, a sulfeneamide compound, a thiuram compound, dithiocarbamic acid compound, 1,8-diazabicyclo(5,4,0)undecene-7 and a weak acid salt thereof, a quaternary ammonium salt compound and mixtures of two or more thereof. However, the vulcanizing agent is not limited thereto.
The primary amine, the secondary amine, and the tertiary amine are preferably an aliphatic or alicyclic amine having 5 to 20 carbon atoms. Examples of preferred amine include n-hexylamine, octylamine, dibutylamine, tributylamine, trioctylamine, di(2-ethylhexyl)amine, dicyclohexylamine, hexamethylenediamine, and the like.
The organic acid that forms a salt with the above-mentioned amine can be a carboxylic acid, a carbamic acid, 2-mercaptobenzothiazole, dithiophosphoric acid and the like. The substance that forms an addition product with the above-mentioned amine can be an alcohol or an oxime. Specific examples of the organic acid salt or the addition product of amine include n-butylamine acetate, dibutylamine oleate, hexamethylenediamine carbamate, a dicyclohexylamine salt of 2-mercaptobenzothiazole and the like.
Examples of the aldehyde-ammonia accelerator include hexamethylenetetramine, a reaction product of acetaldehyde and ammonia, and the like.
The aldehyde-amine accelerator can be, for example, a condensate of an amine with at least one aldehyde having 1 to 7 carbon atoms. Examples of preferred amine can be, for example, aniline, butylamine and the like. Among these, a condensate of aniline with an aldehyde having 1 to 7 carbon atoms is preferable. Specific examples thereof include a condensate aniline with butyraldehyde, a condensate of aniline with heptaldehyde, a condensate of aniline with acetaldehyde and butyraldehyde.
The guanidine accelerator can be diaryl guanidine such as diphenylguanidine, ditolylguanidine or the like.
The thiazole accelerator can be, for example, 2-mercaptobenzothiazole, dibenzothiazyl disulfide, a zinc salt of 2-mercaptobenzothiazole or the like.
The sulfeneamide accelerator comprises a 2-benzothiazylsulfeneamide of a primary amine or a secondary amine represented by the general formula (VI). 
In the formula (VI), R10 and R11 are identical or different, and represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, or an aralkyl group having 1 to 12 carbon atoms, excluding the case where R10 and R11 are both a hydrogen atom. R10 and R11 can be bonded to form a ring via or not via hetero atom(s).
Examples of the primary amine or the secondary amine that forms a sulfeneamide include cyclohexylamine, butylamines, diethylamine, dipropylamines, dioctylamines, dilaurylamines, dicyclohexylamine, piperidine, pipecoline, morpholine, and piperazine.
Specific examples of the sulfeneamide organic vulcanization accelerators include N-ethyl-2-benzothiazylsulfeneamide, N-t-butyl-2-benzothiazylsulfeneamide, N,N-di-isopropyl-2-benzothiazylsulfeneamide, N,N-di-n-butyl-2-benzothiazylsulfeneamide, N,N-di-cyclohexyl-2-benzothiazylsulfeneamide, N-oxydiethylene-2-benzothiazylsulfeneamide and the like.
The thiuram accelerator comprises a thiuram sulfide compound represented by the following general formula (VII). 
In the formula (VII), R12 and R13, R14 and R5 are identical or different, and represent, for example, an alkyl group, an aryl group, a cycloalkyl group, or an aralkyl group. R12 and R13 and/or R14 and R15 can be bonded each other to form a ring via or not via hetero atom(s).
Specific examples of the thiuram accelerators include tetramethylthiuram disulfide, tetramethylthiuram monosulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, dipentamethylenethiuram tetrasulfide and the like.
The dithiocarbamic acid accelerator is exemplified by piperidine pentamethylenedithiocarbamate, zinc dimethyldithiocarbamate, copper dimethylcarbamate or the like.
The above-mentioned accelerator can be in a form of predispersion in an inorganic filler, an oil, a polymer or the like.
The compound 1,8-diazabicyclo(5,4,0)-undecene-7 (hereafter referred to as DBU) is a compound represented by the following formula (VIII). 
The weak acid salt of DBU can be a carbonate, a carboxylate, a salt with a phenolic substance, a salt with an enolic substance, a salt with a thiol or the like. Examples of the acids that constitute these salts include carbonic acid, acetic acid, formic acid, sorbic acid, salicylic acid, xcex2-oxynaphthoic acid, phenol, phthalic acid, cyanuric acid, mercaptobenzothiazole, mercaptobenzoimidazole, and phenolic resins, phenol novolak resins and the like.
Also, it is possible to use DBU by dissolving it into a liquid substance such as a higher alcohol or a glycol; to use DBU in a powder state by dispersing it in an inorganic filler; or to use DBU in a sheet-like or pellet-like form by incorporating it into a polymer substance.
The quaternary ammonium salt compound to be used as the organic vulcanization accelerator is a compound represented by the following general formula (IX). 
In the formula (IX), R16, R17, R18, and R19 are identical or different, and represent a group selected from an alkyl group having 1 to 17 carbon atoms, a cyclohexyl group, a phenyl group, and a benzyl group. Examples of the above alkyl group having 1 to 17 carbon atoms include methyl, propyl, butyl, hexyl, heptyl, octyl, decyl, dodecyl, hexadecyl and the like. X is an anion and can be, for example, a halide anion such as fluoride ion, bromide ion, chloride ion or iodine ion.
These organic vulcanization accelerators may be used either singly or in combination of two or more.
The inorganic vulcanization accelerator (d) can be a compound selected from the group consisting of a basic metal oxide, a basic metal salt, a basic metal hydroxide, a basic silicon dioxide, a silicate, and a hydrotalcite. However, the inorganic vulcanization accelerator (d) is not limited thereto.
Specific examples of the inorganic vulcanization accelerator (d) include magnesium oxide, calcium oxide, aluminum oxide, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, calcium carbonate, basic silicon dioxide, calcium silicate, synthetic hydrotalcite and the like. The inorganic vulcanization accelerator is suitably selected in accordance with the other compounding agents.
Making much of preservation stability of the composition, it is preferable to use a basic metal carbonate. The inorganic vulcanization accelerator can be surface-treated before use.
The inorganic vulcanization accelerator is added preferably at 0 to 20 parts by weight. If it is added at more than 20 parts by weight, the accelerator does not exhibit an increased effect and merely exhibits an effect as a filler.
A polyvalent hydroxyl compound can be added in order to adjust the vulcanization speed. Such a polyvalent hydroxyl compound can be, for example, a trivalent to hexavalent alcohol such as glycerin, ethylene glycol, sorbit, trimethylolpropane or trimethylolethane, but is not limited thereto.
It is also possible to use the above-mentioned inorganic vulcanization accelerator as an additive which is generally called a xe2x80x9cfillerxe2x80x9d in the rubber industry.
One suitable embodiment of the present invention is a chlorine-containing polymer vulcanizing composition obtained by blending, with a chlorine-containing polymer, (a) a zeolite compound, (b) a vulcanizing agent, and (c) an organic vulcanization accelerator comprising a member selected from the group consisting of a primary amine, a secondary amine, a tertiary amine, an organic acid salt or adduct thereof, an aldehyde-ammonia accelerator, an aldehyde-amine accelerator, a guanidine accelerator, a thiazole accelerator, a sulfeneamide accelerator, a thiuram accelerator, dithiocarbamic acid accelerator, DBU and a weak acid salt thereof, a quaternary ammonium salt compound and mixtures of two or more thereof.
A vulcanizing composition in which the above chlorine-containing polymer is a chlorinated polyethylene, an epichlorohydrin polymer, or a chlorosulfonated polyethylene is especially preferable.
The contents of the components in the chlorine-containing polymer vulcanizing composition is such that, with respect to 100 parts by weight of the chlorine-containing polymer, (a) preferably 0.5 to 30 parts by weight, more preferably 5 to 25 parts by weight, of the zeolite compound, (b) preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, of the vulcanizing agent, and (c) preferably 0.5 to 3 mol, more preferably 0.7 to 1.5 mol, of the organic vulcanization accelerator with respect to 1 mol of the vulcanizing agent are blended.
Another suitable embodiment of the present invention is a chlorine-containing polymer vulcanizing composition obtained by blending, with a chlorine-containing polymer, (a) a zeolite compound, (b) a thiadiazole compound, and (c) an organic vulcanization accelerator comprising a member selected from the group consisting of a primary amine, a secondary amine, a tertiary amine, an organic acid salt or adduct thereof, an aldehyde-ammonia accelerator, an aldehyde-amine accelerator, a guanidine accelerator, a thiazole accelerator, a sulfeneamide accelerator, a thiuram accelerator, dithiocarbamic acid accelerator, DBU and a weak acid salt thereof, a quaternary ammonium salt compound and mixtures of two or more thereof, and (d) a compound selected from the group consisting of a basic metal oxide, a basic metal salt, a basic silicon dioxide, a silicate and a hydrotalcite.
A vulcanizing composition in which the above chlorine-containing polymer is chlorinated polyethylene or an epichlorohydrin polymer is especially preferable.
The contents of the components in the chlorine-containing polymer vulcanizing composition is such that, with respect to 100 parts by weight of the chlorine-containing polymer, (a) preferably 0.5 to 30 parts by weight, more preferably 5 to 25 parts by weight, of the zeolite compound, (b) preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, of the vulcanizing agent, (c) preferably 0.5 to 3 mol, more preferably 0.7 to 1.5 mol, of the organic vulcanization accelerator with respect to 1 mol of the vulcanizing agent, and (d) preferably 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight, of the inorganic vulcanization accelerator are blended.
A vulcanized product having good vulcanization properties can be obtained by vulcanizing the above chlorine-containing polymer vulcanizing composition.
In the present specification, xe2x80x9cgood preservation stabilityxe2x80x9d means that the difference (hereafter referred to as xcex94 Vm) between the Vm value (the lowest Mooney viscosity) of the vulcanizing composition immediately after the kneading in the Mooney Scorch test as defined by JIS (Japanese Industrial Standard) K6300 (physical test method for unvulcanized rubber) and the Vm value of the composition in the Mooney Scorch test as measured after it was left to stand for 3 or 7 days at 35xc2x0 C. under humidity of 75% after the kneading, is small.
The tensile physical property (hereafter referred to as initial physical properties) was measured according to JIS K6251, and the compression set was measured according to JIS K6262.
Into the vulcanizing composition of the present invention may be added various additives generally used in the field of the art, for example, a filler, a reinforcing agent, a plasticizer, a stabilizer, an anti-aging agent, a lubricant, a viscosity-imparting agent, a pigment, a flame-retardant, an ultraviolet absorber, a foaming agent, a vulcanization moderator, and the like, if necessary. A short fiber or the like can be added to improve the strength and the rigidity.
In order to prepare the vulcanizing composition of the present invention, the above compounding agents are kneaded by means of an ordinary mixing roll, a Banbury mixer, a twin-screw kneading extruder, or the like kneader, and the kneaded product is then formed into a desired sheet-like shape by means of an oven roll or the like. The molding or the vulcanization is carried out by means of a pressing machine, an extruder, an injection-molding machine or the like to give a rubber product having a desired shape. The vulcanization condition is suitably selected within the range of 100 to 200xc2x0 C. and several minutes to two hours.
A laminated product and a laminated hose having a layer of the above vulcanizing composition can be prepared applying a well-known general lamination process or an extrusion-molding technique. For example, the laminated product can be obtained by laminating the layer of the above vulcanizing composition directly on a layer made of epichlorohydrin rubber, nitrile rubber, nitrile rubber having polyvinyl chloride blended therewith, or acrylic rubber, followed by vulcanizing the composition. Also, the laminated hose can be obtained by molding a hose including an inner layer made of epichlorohydrin rubber, nitrile rubber, nitrile rubber having polyvinyl chloride blended therewith, or acrylic rubber, and an outer layer made of the above vulcanizing composition, followed by vulcanizing the composition.
Specific embodiments for practicing the present invention will be described with reference to the following Examples. However, the present invention is not limited by the following Examples unless it departs from the spirit and scope of the present invention.
The details of the compounding agents used in the Examples and Comparative Examples are as follows.
Chlorinated polyethylene; xe2x80x9cDAISOLAC H-135xe2x80x9d manufactured by DAISO CO., LTD., with a chlorine content of 35%
Epichlorohydrin polymer; ethylene/epichlorohydrin copolymer, xe2x80x9cEPICHLOMER Cxe2x80x9d manufactured by DAISO CO., LTD., with a chlorine content of 25%
Chlorosulfonated polyethylene; xe2x80x9cHYPALON 40xe2x80x9d manufactured by DuPont Dow Elastomers
NBR/PVC: xe2x80x9cNV75xe2x80x9d manufactured by JSR Corporation, a blended product of NBR/PVC=70/30
Reinforcing agent; FEF carbon black, xe2x80x9cSEAST SOxe2x80x9d manufactured by Tokai Carbon Co., Ltd.
Plasticizer I; diisodecyl adipate, xe2x80x9cDIDAxe2x80x9d manufactured by Daihachi Chemical Industry Co., Ltd.
Plasticizer II; xe2x80x9cADEKACIZER RS107xe2x80x9d manufactured by Asahi Denka Kogyo K.K.
Plasticizer III; dioctyl phthalate
Lubricant; sorbitan monostearate, xe2x80x9cSPLENDER R300xe2x80x9d manufactured by Kao Corporation
Acid receiving agent I; synthetic zeolite (I), A-type zeolite, xe2x80x9cMIZUKALIZER DSxe2x80x9d manufactured by Mizusawa Industrial Chemicals, Ltd.
Acid receiving agent II; synthetic zeolite (II), X-type zeolite, xe2x80x9cMolecular Sieves 13Xxe2x80x9d manufactured by Wako Pure Chemical Industries, Ltd.
Acid receiving agent III; highly active magnesium oxide, xe2x80x9cMgO#150xe2x80x9d manufactured by Kyowa Chemical Industry Co., Ltd.
Vulcanizing agent I; 2,4,6-trimercapto-1,3,5-triazine
Vulcanizing agent II; 2-anilino-4,6-dimercaptotriazine
Vulcanizing agent III; 2,5-dimercapto-1,3,4-thiadiazole
Vulcanizing agent IV; 2,2xe2x80x2-dimercapto-5,5xe2x80x2-dithiobis(1,3,4-thiadiazole)
Vulcanizing agent V; 2,2xe2x80x2-di(butoxymethyl)-5,5xe2x80x2-dithiobis(1,3,4-thiadiazole)
Vulcanizing agent VI; dipentamethylenethiuram tetrasulfide
Vulcanizing agent VII; 6-methylquinoxaline-2,3-dithiocarbonate
Organic vulcanization accelerator I; dicyclohexylamine salt of 2-mercaptobenzothiazole
Organic vulcanization accelerator II; dibutylamine
Organic vulcanization accelerator III; condensate of n-butyraldehyde with aniline, xe2x80x9cNOCCEIER 8xe2x80x9d manufactured by Ouchi-Shinko Chemical Industrial Co., Ltd.
Organic vulcanization accelerator IV; N.N-dicyclohexyl-2-benzothiazolylsulfeneamide, xe2x80x9cNOCCELER DZxe2x80x9d manufactured by Ouchi-Shinko Chemical Industrial Co., Ltd.
Organic vulcanization accelerator V; tetrabutylammonium chloride
Organic vulcanization accelerator VI; tetramethylthiuram disulfide, xe2x80x9cNOCCELER TTxe2x80x9d manufactured by Ouchi-Shinko Chemical Industrial Co., Ltd.
Organic vulcanization accelerator VII; N-cyclohexyl-2-benzothiazolylsulfeneamide, xe2x80x9cNOCCELER CZxe2x80x9d manufactured by Ouchi-Shinko Chemical Industrial Co., Ltd.
Organic vulcanization accelerator VIII; a salt of DBU and a phenolic resin, xe2x80x9cP-152xe2x80x9d manufactured by DAISO CO., LTD.
Organic vulcanization accelerator IX; dibenzothiazyl disulfide, xe2x80x9cNOCCELER DMxe2x80x9d manufactured by Ouchi-Shinko Chemical Industrial Co., Ltd.
Organic vulcanization accelerator X; tetramethylthiuram monosulfide, xe2x80x9cNOCCELER TSxe2x80x9d manufactured by Ouchi-Shinko Chemical Industrial Co., Ltd.
Inorganic vulcanization accelerator I; calcium carbonate, xe2x80x9cHAKUENKA Oxe2x80x9d manufactured by Shiraishi Kogyo Kaisha, Ltd.
Inorganic vulcanization accelerator II; resin acid-treated calcium carbonate, xe2x80x9cHAKUENKA CCxe2x80x9d manufactured by Shiraishi Kogyo Kaisha, Ltd.
Inorganic vulcanization accelerator III; light calcium carbonate, xe2x80x9cSILVER Wxe2x80x9d manufactured by Shiraishi Kogyo Kaisha, Ltd.
Inorganic vulcanization accelerator IV; calcium silicate, xe2x80x9cSOLEX CMxe2x80x9d manufactured by TOKUYAMA CORPORATION
Inorganic vulcanization accelerator V; white filler, basic silicon dioxide (pH=10), xe2x80x9cCARPLEX #1120xe2x80x9d manufactured by Shionogi and Co., Ltd.
White filler I; magnesium silicate, xe2x80x9cMISTRON VAPOR TALCxe2x80x9d manufactured by Nihon Mistron Co., Ltd.
White filler II; magnesium silicate, xe2x80x9cHIGH TORONxe2x80x9d manufactured by TAKEHARA KAGAKUKOGYO Co., Ltd.
White filler III; anhydrous aluminum silicate, xe2x80x9cICE BERGxe2x80x9d manufactured by Burgess Pigment Company
Anti-aging agent; nickel dibutyldithiocarbamate, xe2x80x9cNOCRAC NBCxe2x80x9d manufactured by Ouchi-Shinko Chemical Industrial Co., Ltd.
White carbon: xe2x80x9cNip SIL VN-3xe2x80x9d manufactured by Nippon Silica Industrial Co., Ltd.
Light calcium carbonate: xe2x80x9cAKADAMAxe2x80x9d manufactured by Shiraishi Kogyo Kaisha, Ltd.
Calcium hydroxide: xe2x80x9cCARBITxe2x80x9d manufactured by Ohmi Chemical Industry Co., Ltd.
Anti-scorching agent: N-(cyclohexylthio)phthalimide, xe2x80x9cPVIxe2x80x9d manufactured by Monsanto Japan, Ltd.